There is a behavior breaking change on Linux. The temp folder location, where NuGet stores temporary files during its various operations, has changed from /tmp/NuGetScratch to /tmp/NuGetScratch<username>. E.g. for user User1, the temp folder will be /tmp/NuGetScratchUser1.
Summary: What's New in 6.6
[Epic]: Central Package Management improvements for 17.6 - #12413
Issues fixed in this release
DCRs:
Static graph-based restore should always log an error on failure - #12372
Bugs:
Set CentralPackageVersionOverrideEnabled=false in project with CPM broke project restore - #12500
Static graph-based restore crashes on systems with alternate console encodings - #12373
GlobalPackageReference is not working for legacy-style csproj projects - #12368
WebSite projects opened from IIS fail to install packages - #12337
StackOverflow in SemanticVersion.ToString - #12330
Static graph restore failure when referencing unrestorable project - #12322
CPM opt in detection in VS and commandline is different - #12285
Create a .NET project and learn to add packages and manage package dependencies in your project. Use the .NET Core CLI and NuGet registry to add libraries and tools to your C# applications through Visual Studio Code.